Flame hardening mechanism



July 6, 195 HAMMON 3,393,259

FLAME HARDENING ME CHANI SM Filed Nov. 9, 1962 4 Sheets-Sheet 1 4 INVENTOR. 5/ GEORGE L. HAMMON Filed 1962 G. L. HAMMON FLAME HARDENING MECHANISM 4 Sheets-Sheet 3 July 6, 1965 G. L. HAMMON 3,1932% FLAME HARDENING ME CHAN]: S M

Filed Nov. 9, 1962 .4 Sheets-Sheet 4 United States Patent 3,193,269 FLAME HARDENIN G MECHANISM George L. Hammon, Gakiand, Calih, assignor to Hammon Precision Equipment Company, Oakland, Calif., a corporation of California Filed Nov. 9, 1962, Ser. No. 236,569 4 Claims. (Cl. 266) The invention relates to means for flame hardening surfaces of metallic objects such as the rims of wheels, the working surfaces of sheaves or the like. More particularly the invention concerns means for shielding the object during the ignition and adjustment of the source of flame, and for preventing the flame from coming into contact with an area of wheel, sheave or the like which has already been hardened.

The application of flames to metal for the purpose of rapidly hardening the surface thereof to a selected depth without unduly changing the characteristics of the remainder of the metal has long been understood. One method of attempting to harden a rim on a wheel such as a railway car wheel has been to subject the entire rim of a stationary wheel to a source of flames defined by a plurality of torches surrounding the wheel; however, this method suffers first from the inability to provide all of the surrounding torches with an identical working heat, and also renders the method expensive as well as diflicult to control due to the requirement of a great number of torches and attendant supporting equipment such as valves, pressure regulators and sources of combustible gases. Furthermore, practical application of the principle of flame hardening has suffered from the lack of a torch capable of creating suflicient heat to harden the metal to the desired depths; however, with the advent ofthe water cooled torch such as disclosed in my patent application Serial No. 154,952, filed Nov. 27, 1961 and now abandoned, extreme heat is available over a wide range of temperatures, not previously attainable. Due to the cost of this torch, however, it is desirable to use but a minimum of such torches, mounted in a bank, and to rotate the rim of the wheel, or the walls of a sheave relative to the torches. One problem which arises is the protection of the object to be hardened during the ignition and adjustment of the torch or torches to a desired constant temperature. Another problem is to prevent overlapping the application of heat at the beginning and end of the heated areas since the r-e-heating of such areas causes pitting, flaking and other deterioration of the heated surface.

Therefore, a main object of the invention is to provide an improved flame hardening mechanism.

Another object is to provide a unitary shelding means for protecting the object to be hardened during the ignition and adjustment of the torch and also for preventing the re-heating of any portion of an object which is rotated relative to a heating torch.

Another object is to provide a shielding means of the character described in which a coolant is circulated therethrough.

' Still another object is to separately flame harden the two respective surfaces defining the working walls of a sheave.

Other objects and advantages of the invention will be apparent from the following description, given by way of example only, when read with reference to the drawing in which:

FIGURE 1 is a projection of a wheel having a plurality of sheaves with a flame hardening torch and a shield shown in the initial position of the flame hardening process;

FIGURE 2 is a view, showing a portion of the sheaves in cross section, with the torch and the shield shown in the same position as shown in FIGURE 1;

FIGURE 3 is a view, in section, of one of the torches used in the flame hardening process; and FIGURE 4 is a view, partially in section, of the heat shield.

A sheave is generally indicated at It} in FIGURE 1 having a plurality of grooves 11 and an axle having two projecting spindle ends 12, only one of which is shown. The opposite ends 12 are supported in conventional manner, not shown and the sheave is driven by a motor 13 through reduced gearing 14. A switch 15 is connected to a source of current and may be closed to drive the sheave one full revolution after which the switch is opened.

Also shown in FIGURE 1 is an assembly 16 comprising three identical torches 17 (FIGURES 2 and 3) which are suitably supported and fixed relative to the sheave in the position shown in FIGURES 1 and 2. A heat shield 18 (FIGURES l, 2 and 4) is fixed to a tube 19 which is supported by means including a block 20 (FIG- URE 1) of magnetizable material removably mounted on a steel flange 21 integral with the sheave. Clamps 22 and 23 are provided for adjusting the position of the shield 18 relative to the magnetic block 20 and sheave Ill.

A source of liquid coolant such as water, under pressure, is connected to the tube 19 by means of a flexible hose. A second tube 24, connected at one end to the main body portion 25 of the heat shield, is also made of flexible hose, preferebaly of metal, and carries away the water after it is circulated through the heat shield 18.

In the embodiment shown the heat shield is connected to the sheave by the magnetic block 20. This arrangement provides for rapid readjustment of the shield relative to the sheave; however, it will be apparent that other devices such as mechanical clamping devices could be used to connect the heat shield to the flange 21 or other suitable areas of the sheave.

The torch assembly 16 comprises three torches 17. The number of torches used may be varied in accordance with the size of the object to be heat treated, as long as the torches do not extend beyond the heat shield. Since the three torches are identical, the torch assembly is referred to hereinafter as the torch.

Referring to FIGURE 3, the torch 17 is similar to a torch 10 disclosed in my patent application Serial Number 154,952, filed November 17, 1961 and now abandoned, to which reference may be had for a more complete description of the complete torch. In the following description of the torch, reference numerals are used which are identical to those used in the above-mentioned application and, although the configuration of the torch heads is somewhat different in the two applications, the function of the torches in providing great ranges of controlled heat is otherwise identical. FIGURE 3 shows a portion of the main body 79 connected to a second body portion 51. A tube 49 supplies a mixture of combustible gases, under the control of valves and manometers, not shown, to the torch head. The gases flow through apertures 52 in a cap 50' and into a chamber 53. The chamber is formed by a plate 54, a plate 58, a bent extension 56 of a face plate 56, and opposite side walls 59, only one of which is shown. From the chamber 53 the gases flow through a plurality of rows of tubes 57 which are arranged in rectangular array and the gases are emitted under pressure, is pumped through a tube 75 and into a chamber bounded by the plates 56, 58 and 59, which chamber surrounds the tubes 57. Water circulates around the tubes and against the walls of the chamber at a rate of flow suflicient to prevent the deterioration of the torch head otherwise due to over-heating of the same. A tube 7 '7 is provided to discharge water from the chamber described into a chamber 78 formed within body portion 79 to thereby cool the latter. Suitable means, not shown, are provided to carry the water away from the chamber 78, reference being had to the previously mentioned application for a complete description of the torch.

The grooves 11 (FIGURE 1) each comprise a pair of opposite side walls 30 and 31 (FIGURE 2) only one of which is flame hardened at a time.

In the position of the parts shown in FIGURE 2, the face plate 56 of torch 17 faces wall 30, with the shield 18 interposed therebetween, and the opposite plate 58 of the torch lies closely adjacent the wall 31. In this manner the torch may apply heat only to the one wall 30 since the back side of the torch eflectively blocks flames from wall 31, the flames escaping upwardly and outwardly from between the torch and the wall 30, or over the heat shield 18 when the shield is in the position shown in FIGURE 2.

The heat shield (FIGURE 2) includes the body portion 25 and a shielding portion 18. The latter comprises a front plate 33, normally welded to a water jacket 34, but which plate 33 has been removed as shown in FIGURE 4.

The water jacket is made from a solid piece of heatconducting metal such as aluminum with the interior portion milled away to produce four continuous side Walls 35 and an interior baffle 36. Spacer stops 37, connected between the jacket 34 and the front plate 33, are located at intervals within the water jacket and are provided toprevent collapse or buckling of the shield 18 when exposed to the extremely high temperature heat of the torch. Water, under pressure is pumped through the tube 19 (FIGURE 2) and into the main body portion 25 which is hollow. From there the water flows through an inlet hole 38 (FIGURE 4) in the water jacket and flows in a general let hole which is in direct communication with the outlet pipe 24' (FIGURE 2). For this purpose the pipe 24 passes completely through the body portion to connect with the outlet hole 39. Thus, a path of flow is provided for the water, or other coolant which is pumped continuously through the heat shield.

In the initial position of the parts shown in FIGURES 1 and 2, the trailing edge of the shield, which is the rightmost end as seen in FIGURE 1, is located on an index point, scribed, or otherwise marked, on the sheave ll. With the coolant being pumped through the heat shield, the torch 16 is ignited and adjusted to a predetermined operating temperature. During this adjustment of the torch, the shield 18 protects the wall and prevents the heating and pitting of the wall which occurs when no heat shield is present. The switch 15 is then closed to cause the motor to drive the spindle 12 and the sheave 10, the arrangement being that the motor drives the sheave in a counterclockwise direction. The sheave and the shield, attached thereto, are rotated relative to the torch, the flexible tubing connected to the shield permitting movement of the shield while coolant is continuously pumped therethrough. The motor drives the sheave at a constant rate and the torch flame hardens the. wall of. the V position.- The shield is then replaced on the sheave, while the flame hardening process continues, with the leading edge of the shield (the leftmost end as seenin FIGURE 1) being located on the index point of the sheave. Such relocation of the shield permits the portion of the wall previously covered to be flame hardened, while preventing the re-heating or hardening of the wall which has already been hardened. After such hardening is completed, the shield is again located opposite the torch, whereupon the torch is extinguished and the motor switch is opened.

It will be observed that the length of the shield is not critical, the main requirement being that it be of sufficient length to protect the sheave during the ignition and adjustment of the torch. With this requirement in mind, the shield is usually made longer than the length of the torch, and in those cases where a torch of lesser length is used, the same shield may be used.

I claim: I

1. A machine for flame hardening the continuous periphery of a circular metallic object comprising, in combination with means for rotatably mounting said object,

(a) atorch,

(b) means for holding the torch in a fixed position,

(c) means for rotating said object relative to the torch to flame harden a continuous peripheral surface area of the object, a

(d) a shield to prevent a torch flame from contacting said object, and I (e) means for detachably fixing said shield in a first and a second position on said object for rotation therewith,

said shield being operable in the first fixed position to prevent said torch flame from contacting a first selected area of the object and being operable in the second fixed position to prevent said torch flame from contacting a previously flame treated area of the object. 7

2. A flame hardening machine as defined in claim 1 including means for rotating the object at a constant rate relative to the torch.

3. Means for flame hardening a selected one of a pair of side walls of a sheave or the like comprising;

(a) means for rotating the sheave about its axis,

(b) a flame hardening torch having a heating head of such configuration that a plurality of flames are dir'ected at only one side wall of the sheave,

(c) means for holding the torch head in a selected fixed position relative to the sheave throughout 360 of rotation of the sheave,"

(d) a shield which is detachably secured to the sheave prior to igniting the torch and which shield is located between the torch and said selected wall of the sheave to deflect flames from said sheave,

(1) said shield having a leading edge and a trailing edge as defined by the direction of movement of the shield and sheave relative to the torch,

(2) and said trailing edge being aligned with an index point on said sheave,

(3) said shield moving with the sheave out from beneath the ignited torch to permit flame hardening of the selected wall during rotation of the sheave and (4) said shield being capable of being detached from said sheave during the hardening process and being re-attached with the leading edge'of the shield coinciding with said index point prior to completion of 360 of movement of the sheave to thereby prevent re-hardening of any portion of said wall, but permitting hardening of the entire wall.

4. A flame hardening means as defined in claim 3 in which the torch head is so shaped that the side of the head opposite the flame emitting side is contoured to lie closely 5 6 adjacent the sheave wall which is not being hardened and FOREIGN PATENTS to thereby protect said latter Wall from flames. 946,203 7 56 Germany.

References Cited by the Examiner UNITED STATES PATENTS 2,067,549 1/37 Sykes 26623 X 2,207,102 7/40 Nielsen 26623 X JAMES H. TAYMAN, IR., Examiner.

MORRIS O. WOLK, Primary Examiner. 

1. A MACHINE FOR FLAME HARDENING THE CONTINUOUS PERIPHERY OF A CIRCULAR METALLIC OBJECT COMPRISING, IN COMBINATION WITH MEANS FOR ROTATABLY MOUNTING SAID OBJECT, (A) A TORCH, (B) MEANS FOR HOLDING THE TORCH IN A FIXED POSITION, (C) MEANS FOR ROTATING SAID OBJECT RELATIVE TO THE TORCH TO FLAME HARDEN A CONTINUOUS PERIPHERAL SURFACE AREA OF THE OBJECT, (D) A SHIELD TO PREVENT A TORCH FLAME FROM CONTACTING SAID OBJECT, AND (E) MEANS FOR DETACHABLY FIXING SAID SHIELD IN A FIRST AND A SECOND POSITION ON SAID OBJECT FOR ROTATION THEREWITH, SAID SHIELD BEING OPERABLE IN THE FIRST FIXED POSITION TO PREVENT SAID TORCH FLAME FROM CONTACTING A FIRST SELECTED AREA OF THE OBJECT AND BEING OPERABLE IN THE SECOND FIXED POSITION TO PREVENT SAID TORCH FLAME FROM CONTACTING A PREVIOUSLY FLAME TREATED AREA OF THE OBJECT, 